Discovered: New Solar System that Looks Like Ours

Our solar system now has a cousin! Astrophysicists at the MIT have discovered another planetary system that resembles ours. This system is around 10000 light years away from earth.

How do you define ‘similar’? Does that mean the presence of an Earth with life? Well, not quite. Our solar system has the unique property that the orbits of its planets are nearly perfectly aligned in a plane, like lanes on a track field. This is quite in contrast with most exoplanetary systems, some of which have quite eccentric orbits. For the first time, another planetary system with perfectly aligned orbits has been discovered.

A cartoon depicting the coplanar orbits of our solar system. [Image Credit: universetoday, NASA/JPL-Caltech/T.Pyle]

Pointing Telescopes at a Star Called Kepler-30

Researchers at MIT trained their telescopes—one particular telescope, in fact, called the Kepler Telescope—on a star called Kepler-30. This star has three planets. Because the star is so far away, the only way to study it is to measure the small amount of light it radiates. They tried to determine the orbits of these planets by observing decreases in light intensity from this planet and its sunspots, which would occur when a planet transited across the observed face of the star. These sunspots themselves are moving with respect to the earth because of the star’s rotation about its axis. Thus, every time a planet transits across the star, it blocks a sunspot at a different position.

Using the timing of this data, the orbits of the 3 planets could be determined, and they were found to lie on a plane, exactly like the solar system. The orbits of the planets were also in a plane perpendicular to the star’s axis of rotation. These results were published in the journal Nature.

It’s telling me that the solar system isn’t some fluke,” says Josh Winn, an associate professor of physics at MIT and a co-author. “The fact that the sun’s rotation is lined up with the planets’ orbits, that’s probably not some freak coincidence.”

How were Systems with Non-Coplanar Orbits Formed?

This finding also backs theories on system of other planets called ‘hot Jupiters’. These are large planets with misaligned orbits around their stars. It is hypothesized that ‘planetary scattering’ led to their misaligned orbits. This theory says that these stars came close to other giant stars in the early stages of planetary system formation, and threw some planets out of the system while bringing others closer to their stars. The existence of another non-hot Jupiter system with planets far away from each other gives further credence to this hypothesis.

“We’ve been hungry for one like this, where it’s not exactly like the solar system, but at least it’s more normal, where the planets and the star are aligned with each other,” Winn says. “It’s the first case where we can say that, besides the solar system.” You can read about this research here.

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Shweta Ramdas

Beginning life as a grad student studying human genetics.